Determination Method and Processing Method of Machined Surface of Plate-Like Material, and Apparatus for Use in said Methods

ABSTRACT

Provided is a surface treatment method for performing machining such as cutting work, grinding, and electrical discharging to a plate-like material with two- or three-dimensional deformation to realize a uniform thickness. This method includes the steps of mounting the plate-like material on a surface plate, setting a coordinate axis in a plane direction of the plate-like material to be X, Y and setting a coordinate axis in a height direction of the plate-like material to be Z, virtualizing a surface containing an origin of the measured Z direction, measuring a height Z 1-n  from the origin in an arbitrary plane position, and inclining and cutting the plate-like material so that an absolute value of a difference between a maximum value Z max  and a minimum value Z min  of the obtained height data will be minimum. Although a ceramic sintered plate such as a sputtering target or a metal plate prepared by metal rolling or forging, in most instances, is subject to two- or three-dimensional deformation as a result of thermal stress or machining stress during the manufacturing process, this invention is able to obtain a flat plate-like material having a uniform thickness and minimal machining costs from a plate-like material with two- or three-dimensional deformation.

TECHNICAL FIELD

The present invention relates to a determination method and a machiningmethod of a machined surface of a plate-like material in a surfacetreatment for obtaining a flat plate-like material having a uniformthickness and minimal machining costs from a plate-like material withtwo- or three-dimensional deformation, as well as to an apparatus to beused in these methods.

BACKGROUND ART

A ceramic sintered plate such as a sputtering target or a metal plateprepared by metal rolling or forging, in most instances, is subject totwo- or three-dimensional deformation as a result of thermal stress ormachining stress during the manufacturing process. In order to obtain aflat plate-like material having a uniform thickness from a plate-likematerial with such three-dimensional deformation, machining such ascutting work, grinding, and electrical discharging is performed.

Conventionally, a material with this kind of deformation was subject tothe foregoing processes by an operator setting such material directly ona processing machine, or the operator would roughly measure thedeformation of the individual plate-like materials in advance with astraight edge or the like, and insert a spacer during the stage ofsetting such materials in the processing machine in order to maintainflatness. Nevertheless, the current status is that the foregoing methodsare conducted based on the operator's instincts.

For instance, when grinding a material based on the operator'sinstincts, even in the operator is an expert, he/she will need toperform such grinding more than necessary in order to obtain a plane.This is because it will not be possible to maintain the accuracy offlatness or uniform thickness if the operator does not perform suchexcessive grinding. Therefore, it was necessary to set the machiningcosts of the material itself higher, and this led to deterioration inthe yield. In addition, this also led to increased operation time of theprocessing machine as a matter of course.

As conventional technology, there are an apparatus capable of preciselymeasuring the thickness of respective warped plate-shaped works (forinstance, refer to Patent Document 1), a warped measuring devicecomprising a measurement reference unit, a measurement unit, adisplacement measurement unit for converting into electrical signals, awarp measure display unit, and a control unit (for instance, refer toPatent Document 2), a manufacturing methods of a ceramic productcomprising the steps of pressurizing and molding ceramic materialpowder, irradiating a light beam on the surface thereof, and measuringthe surface status upon receiving the reflected light (for instance,refer to Patent Document 3), a size measurement ceramic gauge providedwith a stepwise portion (for instance, refer to Patent Document 4), aplate flatness measuring device comprising a downward measuring unit formeasuring the flatness, a plate support pin, a vertical motion actuator,and a pressure regulation unit (for instance, refer to Patent Document5), and a method for measuring the shape irregularity of a ceramicsubstrate using infrared thermography (for instance, refer to PatentDocument 6).

Nevertheless, the foregoing conventional technologies are methods ordevices for measuring flatness, measuring displacement or measuringshape irregularities, and do not provide the concept of improving theyield upon performing surface treatment with machining such as cuttingwork, grinding, and electrical discharging.

[Patent Document 1] Japanese Patent Laid-Open Publication No. H6-66549

[Patent Document 2] Japanese Examined Patent Application Publication No.S59-36202

[Patent Document 3] Japanese Patent Laid-Open Publication No. S63-173607

[Patent Document 4] Japanese Patent Laid-Open Publication No. H7-128002

[Patent Document 5] Japanese Patent No. 3418819

[Patent Document 6] Japanese Patent No. 3183935

SUMMARY OF THE INVENTION

As described above, a ceramic sintered plate such as a sputtering targetand a metal plate prepared by metal rolling or forging, in mostinstances, are subject to two- or three-dimensional deformation as aresult of thermal stress or machining stress during the manufacturingprocess. Thus, an object of the present invention is to obtain aplate-like material having flat and uniform thickness from a plate-likematerial with two- or three-dimensional deformation and to provide adetermination method of a machined surface of a plate-like material in asurface treatment such as cutting work, grinding and electricaldischarging to obtain a plate-like material having minimal machiningcosts and uniform thickness, as well as to an apparatus to be used inthese methods.

In order to achieve the foregoing object, as a result of intense study,the present inventors discovered that it is possible to obtain a flatplate-like material having uniform thickness with a favorable yield bymeasuring the height Z_(1-n) from a reference plane in an arbitraryplane position, measuring an absolute value of a difference of a maximumvalue Z_(max) and a minimum value Z_(min) of the obtained height data,and performing surface treatment by adjusting the inclination of theplate-like material on a block so that the machining costs will beminimal.

Based on the foregoing discovery, the present invention provides:

1) A method of determining a machined surface of a plate-like materialcapable of minimizing machining costs upon machining the plate-likematerial with two- or three-dimensional deformation to realize a uniformthickness, comprising the steps of mounting the plate-like material on asurface plate, setting a coordinate axis in a plane direction of theplate-like material to be X, Y and setting a coordinate axis in avertical direction of the plate-like material to be Z, virtuallyconfiguring with a computer a plane ABCD in which a distance in thevertical direction from the surface plate is H, measuring a prescribedcoordinate number while changing a distance (height) Z₀₀ from the planeABCD in the coordinates (X, Y) of the plane ABCD to the coordinates (X,Y) of an upper surface of the plate-like material as an object to bemeasured while changing (X, Y), searching for a maximum value Z₀₀ (max)and a minimum value Z₀₀ (min) from all coordinate points to calculate adifference D₀₀ thereof, subsequently fixing end A and end B or end A andend C of the plane ABCD, inclining the plane ABCD against the surfaceplate by sequentially raising and lowering either end C or end B in aprescribed height at a time within a prescribed range in the Z axisdirection, measuring the height from the plane ABCD to the upper surfaceof the plate-like material regarding all coordinate points (X, Y) on theplane ABCD as with the initial measurement when representing a newheight Zmn by measuring a corresponding coordinate point of a materialfrom the respective coordinates of the plane ABCD each time theinclination is changed one unit, repeating the search for the maximumvalue Zmn (max) and the minimum value Zmn (min) to calculate thedifference D_(mn) regarding all inclination conditions, and deciding thesmallest value of the obtained height difference D_(00-mn) as a parallelplane of a plane in which the plane ABCD (Dmin) will be of a minimummachining cost;

2) The method of determining a machined surface [of a plate-likematerial] according to paragraph 1) above, wherein, upon reversing andmounting the plate-like material on the surface plate of the processingmachine, a measurement point in which a height Z from the plane ABCD tothe plate-like material is a smallest value in the determined minimummachined plane ABCD is searched, and the measurement point is set as apoint that comes in contact with the surface plate;

3) The method of determining a machined surface [of a plate-likematerial] according to paragraph 1) or paragraph 2) above, wherein, uponreversing and mounting the plate-like material on the surface plate ofthe processing machine, the smallest value Zmin of the height Z from theplane ABCD to the plate-like material is subtracted from a height of themeasurement point of four corners of the plate-like material in advance,and the obtained value is made to be a thickness of a spacer to beinserted in the four corners upon setting the plate-like material on theprocessing machine;

4) The method of determining a machined surface [of a plate-likematerial] according to paragraph 3) above, wherein, when there isvariation in the plate-like material thickness, the thickness of thespacer is corrected for the amount of the variation;

5) The method of determining a machined surface of a plate-like materialaccording to any one of paragraphs 1) to 4) above, wherein the height ofboth the X direction and the Y direction of the coordinate axis of theplate-like material is measured at a position of a pitch which is 20 mmor less;

6) The method of determining a machined surface of a plate-like materialaccording to any one of paragraphs 1) to 5) above, wherein the distanceZ with the plate-like material is measured with a laser distance sensoror a contact distance sensor.

7) The method of determining a machined surface of a plate-like materialaccording to any one of paragraphs 1) to 6) above, wherein, based onsaid data, inclination of a biaxial rotary-type machining table of anNC-controllable processing machine is adjusted in substitute formanually inserting a spacer at the four corners of the plate-likematerial;

8) A machining method of deciding a machined surface of a plate-likematerial with the method according to any one of paragraphs 1) to 7)above, and, based on the decided machined surface, performing machiningsuch as cutting work, grinding, and electrical discharging to aplate-like material with two- or three-dimensional deformation torealize a uniform thickness;

9) A machining method of deciding a machined surface of a plate-likematerial with the method according to any one of paragraphs 1) to 7)above, and, based on the decided machined surface, surface grinding onesurface of the plate-like material, and thereafter reversing andmounting the plate-like material on the surface plate to process therear surface; and

10) A machining method of immovably fixing a plate-like material on theprocessing machine via adhesion or electromagnetic adsorption, decidingoptimal inclination conditions through measurement with the methodaccording to any one of paragraphs 1) to 7) above, thereafter using abiaxial inclination mechanism of the surface plate of the processingmachine, without reversing the material, to incline the surface plate inparallel to a plane obtained with the optimal inclination conditions,and machining the material in this state.

The present invention further provides:

11) An apparatus of determining a machined surface of a plate-likematerial capable of minimizing machining costs upon machining theplate-like material with two- or three-dimensional deformation torealize a uniform thickness, comprising a system for mounting theplate-like material on a surface plate, setting a coordinate axis in aplane direction of the plate-like material to be X, Y and setting acoordinate axis in a vertical direction of the plate-like material to beZ, and virtually configuring with a computer a plane ABCD in which adistance in the vertical direction from the surface plate is H; a systemfor measuring a prescribed coordinate number while changing a distance(height) Z₀₀ from the plane ABCD in the coordinates (X, Y) of the planeABCD to the coordinates (X, Y) of an upper surface of the plate-likematerial as an object to be measured while changing (X, Y), searchingfor a maximum value Z₀₀ (max) and a minimum value Z₀₀ (min) from allcoordinate points to calculate a difference D₀₀ thereof; a system forsubsequently fixing end A and end B or end A and end C of the plane ABCDand inclining the plane ABCD against the surface plate by sequentiallyraising and lowering either end C or end B in a prescribed height at atime within a prescribed range in the Z axis direction; a system formeasuring the height from the plane ABCD to the upper surface of theplate-like material regarding all coordinate points (X, Y) on the planeABCD as with the initial measurement when representing a new height Zmnby measuring a corresponding coordinate point of a material from therespective coordinates of the plane ABCD each time the inclination ischanged one unit; and a system for repeating the search for the maximumvalue Zmn (max) and the minimum value Zmn (min) to calculate thedifference D_(mn) regarding all inclination conditions; wherein theinclination conditions of the plane ABCD having the smallest value ofthe obtained height difference D_(00-mn) are made to be a parallel planeof a plane in which the plane ABCD (Dmin) will be of a minimum machiningcost;

12) The apparatus for determining a machined surface of a plate-likematerial according to paragraph 11) above, wherein, upon reversing andmounting the plate-like material on the surface plate of the processingmachine, a measurement point in which a height Z from the plane ABCD tothe plate-like material is a smallest value in the determined minimummachined plane ABCD is searched, and the measurement point is set as apoint that comes in contact with the surface plate;

13) The apparatus for determining a machined surface according toparagraph 11) or paragraph 12) above, wherein, upon reversing andmounting the plate-like material on the surface plate of the processingmachine, the smallest value Zmin of the height Z from the plane ABCD tothe plate-like material is subtracted from a height of the measurementpoint of four corners of the plate-like material in advance, and theobtained value is made to be a thickness of a spacer to be inserted inthe four corners upon setting the plate-like material on the processingmachine;

14) The apparatus for determining a machined surface according toparagraph 13) above, wherein, when there is variation in the plate-likematerial thickness, the thickness of the spacer is corrected for theamount of the variation;

15) The apparatus for determining a machined surface of a plate-likematerial according to any one of paragraphs 11) to 14) above, furthercomprising machining equipment for performing machining such as cuttingwork, grinding, and electrical discharging to a plate-like material withtwo- or three-dimensional deformation to realize a uniform thickness;

16) The apparatus for determining a machined surface of a plate-likematerial according to any one of paragraphs 11) to 15) above, furthercomprising an apparatus for surface grinding one surface of theplate-like material, and thereafter reversing and mounting theplate-like material on the surface plate to process the rear surface;

17) The apparatus for determining a machined surface of a plate-likematerial according to any one of paragraphs 11) to 16) above, furthercomprising an apparatus for measuring the height of both the X directionand the Y direction of the coordinate axis of the plate-like material ata position of a pitch which is 20 mm or less;

18) The apparatus for determining a machined surface of a plate-likematerial according to any one of paragraphs 11) to 17) above, furthercomprising an apparatus for measuring the distance Z with the plate-likematerial with a laser distance sensor or a contact distance sensor;

19) The apparatus for determining a machined surface according toparagraph 11) or paragraph 12) above, further comprising an apparatusfor adjusting, based on said data, the inclination of a biaxialrotary-type machining table of an NC-controllable processing machine insubstitute for manually inserting a spacer at the four corners of theplate-like material; and

20) A flattening device such as a surface grinding machine, a millingmachine, or an electrical discharge machine comprising the apparatusaccording to any one of paragraphs 11) to 19) above.

[Effect of the Invention]

The present invention yields a superior effect in that it is able toobtain a flat plate-like material having a uniform thickness from aplate-like material with complex two- or three-dimensional deformationby performing surface treatment to a product with machining such ascutting work, grinding, and electrical discharging with minimalmachining cost.

In other words, specifically, when manufacturing a product with apredetermined thickness, it is possible to reduce the margin in theunprocessed thickness of the material, whereby the machining cost can beset lower than conventional methods, yield can be improved, andmachining time can be shortened.

Further, when manufacturing a material without any designated thicknessfrom a deformed material via machining, it is possible to thicken thethickness of products of conventional art.

In addition, no more trial and error will be required in setting amaterial on a processing machine table, and machining at a minimummachining cost can be easily performed even when the operator is not anexpert.

As described above, the present invention yields significant effects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram in a case of measuring the height (Zm,n) up to an arbitrary plane position (xm, yn) of a material S from theposition of a sensor of a measuring device as the origin of the heightdirection;

FIG. 2 is an explanatory diagram in a case of virtually configuring aplane (ABCD) that is the same size as the material S in a computer,fixing an end A of the plane ABCD, and moving only an end C to aprescribed height; and

FIG. 3 is an explanatory diagram in a case of virtually configuring aplane (ABCD) that is the same size as the material S in a computer,fixing an end A of the plane ABCD, and moving ends B and C to aprescribed height.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is now explained in detail with reference to theattached drawings as necessary. The following explanation, however, ismerely for explaining the present invention in an easy-to-understandmanner, and the invention is not limited to this explanation. In otherwords, any modifications, other structures or configurations based onthe present invention are covered by the invention as a matter ofcourse.

A plate-like material with complex two- or three-dimensional deformationsuch as a ceramic sintered plate or a metal plate prepared by metalrolling or forging is immovably placed on a surface plate having acertain degree of flatness.

For the sake of explanation, the coordinate axis in the plane directionof this material is set as X, Y and the coordinate axis in the heightdirection is set as Z. A measuring device such as a laser distancemeasuring device capable of retaining a certain degree of height from asurface plate and moving the surface plate in parallel to the XYdirection is mounted on the surface plate. A plane parallel to a surfaceplate in which the Z axis origin of the sensor moves is set as plane P.

As shown in FIG. 1, the height (Zm, n) from the sensor position of themeasuring device that is made to be the origin of the height directionto an arbitrary plane position (Xm, Yn) of the material S are measured.It is necessary to change the X, Y coordinate points of measurementdepending on the deformation of the product, and, for instance, the Xdirection and the Y direction are both made to be a pitch of 20 mm.

As the method for measuring the height, an appropriate method such asusing a laser distance sensor or a contact distance sensor may beemployed. Incidentally, height (Z coordinate) used herein refers to thedistance of the perpendicular line from the coordinates (X, Y) of planeP on which the sensor of the measuring device moves to the point inreaching the material S surface.

The positioning accuracy of the X, Y coordinates and the measurementaccuracy of the Z coordinate are determined based on the degree ofdemanding the reduction in machining costs of the material S. Forexample, with an expensive material such as a noble metal, it iseffective to improve the measurement accuracy of the apparatus to seekthe improvement in the yield upon cutting a product plate from thematerial. Nevertheless, the accuracy can be low when using aninexpensive material such as steel.

Further, when much machining time is required such as in machiningceramics, it is effective to improve the accuracy of the apparatus andreduce the machining cost and shorten the machining time. Nevertheless,the measurement accuracy can be low when using a metal material withfavorable machinability in which the machining time will not be aproblem.

According to the size of the material, all heights (Z0, 0 to Zx, y) from(X0, Y0) to (Xx, Yy: final coordinates) are measured. The result of allmeasurements can be temporarily stored in a recording device of acomputer in a format such as a tabular form so data can be organizedeasily.

Foremost, the origin in the Z direction of the measuring device; thatis, the plane S of the height H is virtualized. It can be said that theheight of the respective measurement points is the height from thevirtual surface.

The difference of the maximum value (Zmax) and the minimum value (Zmin)of the height data is the current machining cost. This is because, ifthe material S is set on the processing machine table in the currentstatus, the cutting tool of the processing machine will start to come incontact from the minimum point (Zmin) of the height, and the material Swill become flat when such cutting tool reaches the maximum point (Zmax)together with the advancement of machining. Therefore, in order toenable the machining of the material with minimal machining costs, thematerial S should be inclined so that the absolute value of thedifference between the heights (Zmin) and (Zmax) becomes minimal.

Nevertheless, since a material is deformed to begin with, it is somewhatcomplicated to calculate changes in the height when inclining thematerial. Thus, instead of inclining the material S, the height can berecalculated by inclining the plane P.

Although there are numerous methods of inclining the plane P with acomputer, the following method has been adopted since it is based onfact, calculation is easy, and the calculation result can be directlyreflected on the thickness of a spacer. A plane (ABCD) on the plane Pand of the same size as the material S is virtually configured in thecomputer. Here, the height (Zm, n) from the coordinates (Xm, Yn) in theplane ABCD to the coordinates (Xm, Yn) of the material is the initiallymeasured height.

The height of the coordinates (m, n) of the plane ABCD is represented as(Zm, n)/0.0, 0.0. 0.0, 0.0 shows that the measured value has not beenmanipulated in any way; that is, it shows that the plane (ABCD) is notinclined.

The maximum value (Zm, n) 0.0, 0.0 max and the minimum value (Zm, n)0.0, 0.0 min of Z (m, n) 0.0, 0.0 regarding all measured coordinatepoints are searched, and the difference H0.0, 0.0 is calculated with thefollowing equation.H0.0, 0.0=(Zm, n) 0.0, 0.0 max−(Zm, n) 0.0, 0.0 min

Subsequently, as shown in FIG. 2 and FIG. 3, end A of the plane ABCD isfixed, and ends B, C are sequentially raised and lowered (for instance,±3.0 mm) in a prescribed height (for example, 0.1 mm pitch) within aprescribed range in the Z axis direction. FIG. 2 illustrates a case offixing end A of the plane ABCD and moving only end C to a prescribedheight, and FIG. 3 depicts a case of fixing end A of the plane ABCD andmoving ends B, C to a prescribed height.

End D is automatically decided when ABC are determined. For instance,foremost, when B is set to −3.0 mm and C is set to −3.0 mm, the distancefrom the respective coordinates of the plane ABCD to the correspondingcoordinate point of the material is calculated, and the new height (Zm,n) is set to −3.0, −3.0. −3.0, −3.0 represents that point B is lowered3.0 mm from the origin, and point C is lowered 3.0 mm from the origin.

This operation is performed to all measurement points, the maximum value(Zm, n) −3.0, −3.0 max and the minimum value (Zm, n) −3.0, −3.0 min of Z(m, n) −3.0, −3.0 are searched, and the difference H−3.0, −3.0 iscalculated based on the following equation.H (−3.0, −3.0)=(Zm, n)−3.0, −3.0 max−(Zm, n)−3.0, −3.0 min

Subsequently, C is set to −2.9 mm, and the same operation is repeated toseek H (−3.0,−2.9). Similarly, C is increased 0.1 mm at a time, and allcorresponding heights H (−3.0, C) (C=−2.9, H−2.8, H−2.7 . . . H 0 . . .H+3.0) are sought.

After this operation is complete, B is set to −2.9, and the sameoperation is repeated while increasing C to −3.0 to +3.0 to seek allheights H (−2.9, C). Further, B is set to −2.8, −2.7, −2.6 . . . 0 . . .+3.0, and all corresponding heights H (B, C) are sought. In thisexample, there are 60 ways for B and 60 ways for C, so there are60×60=3,600 ways for H (B, C).

Among such 3,600 ways, the H (B, C) showing the smallest value among theheights H; that is, the combination of H (B, C) min will be the planethat is parallel to the plane of the minimum machining cost formachining the material.

Incidentally, with the distance from the plane ABCD to the materialsurface, since the coordinates are out of alignment due to theinclination of the plane, it is necessary to correct such misalignmentin the amount of the angle in order to ensure accuracy. Nevertheless,since the amount of inclination against the length of the material issmall, this can be ignored in terms of execution.

Subsequently, among the measurement points of the H (B, C) min, themeasurement point in which the height Z from the plane ABCD to thematerial is the smallest value; namely, Zmin/H (B, C) min, is searched.When actually engaging in machining, since the material is reversedupside down and set on the surface plate of the processing machine, thisis the only point that comes in contact with the surface plate. However,when there are a plurality of points to become Zmin/H (B, C) min, allpoints will come in contact with the surface plate.

Subsequently, Zmin/H (B, C) min is subtracted from the height Z (X0,Y0), Z (Xx, Y0), Z (X0, Yy), Z (Xx, Yy) in the H (B, C) min of themeasurement point of the four corners of the material. The valueobtained thereby will become the thickness of a spacer to be insertedbelow the four corners upon setting the material on the processingmachine.

In a practical sense, since the sensor is positioned at the upper part,the material is reversed upside down when being mounted on theprocessing machine. Thereupon, when the thickness of the material isdifferent depending on the location, the height of the spacer determinedwith the foregoing method may not necessarily realize an optimalsurface. However, when it is possible to ignore variations in thethickness of the material as in this example, it is not necessary tocorrect such variations.

When variations in the thickness of the material become a problem, thepractical optimal surface can be easily determined by measuring thethickness of the four corners in advance, calculating the average valueAve. (X0Y0, XZY0, X0YZ, XZYZ), and adding or subtracting the differencebetween the average value and the thickness of the respective corners toor from the spacer height.

The material is reversed upside down from the time of measurement andfixed to the table of a plane processing machine such as a surfacegrinding machine or a front milling machine in a state with spacers laidunder the prescribed four corners. If machining is performed in thisstate, it is possible to obtain a plane without any uncut portions withminimal machining cost.

Further, by providing to the processing machine an apparatus that is XYbiaxially movable and capable of setting the inclination of the planewith such movement, and providing an inclination that realizes a surfacewhere the optimal surface calculated with this apparatus is symmetricalto the Z axis direction in the XY plane, it is possible to realize anoptimal surface without a spacer. However, in the foregoing case, it isdesirable to insert a spacer for correcting the difference in heights atthe four corners of the material when the plane ABCD is horizontal; thatis, in the state of the initial measurement in order to prevent thematerial from moving.

The height of this spacer is equivalent to a value obtained bysubtracting the height of a measurement point of a location with thelowest height from the height from the plane ABCD during the initialmeasurement to the measurement point of the four corners.

In addition to virtualizing the surface containing the original of the Zdirection measured with a computer, the absolute value of the differencebetween the maximum value Z_(max) and the minimum value Z_(min) of theheight data is sought.

The height of the virtual plane can be calculated based on the followingequation. However, displacement in the X, Y direction as a result ofinclining the sintered body can be ignored in view of the size of thework, and the Z coordinate axis of the grid point of the virtual planecan be sought with the following equation.Z=Z1/(n−1)*i+Z2/(m−1)*j

Wherein n is the number of measurement points in the X direction, m isthe number of measurement points in the Y direction, and i and jrespectively show the measurement order from point 0.

As described above, inclination of the plate-like material can beadjusted by inclining the plate-like material in a computer and placinga spacer between the surface plate and the plate-like material based onthe foregoing data. Further, this data can also be used to adjust theinclination of the biaxial rotary-type machining table of anNC-controllable processing machine.

Accordingly, it is possible to perform surface treatment such as cuttingwork, grinding, and electrical discharging to a plate-like material withcomplex two- or three-dimensional deformation to obtain a product withminimum machining cost. Further, after surface grinding one surface ofthe plate-like material as described above, the rear side can also bemachined upon reversing and mounting the plate-like material on thesurface plate.

INDUSTRIAL APPLICABILITY

The surface treatment method of a plate-like material according to thepresent invention yields a superior effect in that it is able to obtaina flat plate-like material having a uniform thickness from a plate-likematerial with complex two- or three-dimensional deformation byperforming surface treatment to a product with machining such as cuttingwork, grinding, and electrical discharging with minimal machining cost.

In other words, specifically, when manufacturing a product with apredetermined thickness, it is possible to reduce the margin in theunprocessed thickness of the material, whereby the machining cost can beset lower than conventional methods, yield can be improved, andmachining time can be shortened.

Further, when manufacturing a material without any designated thicknessfrom a deformed material via machining, it is possible to thicken thethickness of products of conventional art.

In addition, no more trial and error will be required in setting amaterial on a processing machine table, and machining at a minimummachining cost can be easily performed even when the operator is not anexpert.

As described above, since the present invention is able to obtain a flatplate-like material having a uniform thickness by performing surfacetreatment with machining such as cutting work, grinding, and electricaldischarging with minimal machining cost, it is suitable for themanufacture of a relatively expensive sputtering target or the like.

1. A method of determining a machined surface of a plate-like materialcapable of minimizing machining costs upon machining the plate-likematerial with two- or three-dimensional deformation to realize a uniformthickness, comprising the steps of: setting a surface plate surface of ameasuring device as coordinates (X,Y), setting orthogonal coordinates(X,Y,Z) formed from a Z coordinate that is perpendicular to thecoordinates (X,Y) on the surface plate, mounting the plate-like materialas an object to be measured on the surface plate, and virtuallyconfiguring with a computer a plane ABCD that is parallel to the XYplane in which a distance from the surface plate is H, measuring adistance (height) Zm,n from coordinates (Xm, Yn) of the virtual planeABCD to coordinates (Xm, Yn) of an upper surface of the plate-likematerial as an object to be measured m times in the X direction and ntimes in the Y direction while changing the coordinates (X, Y) for allareas of the plate-like material, and storing the measured data in astorage apparatus of the computer; searching for a maximum value of Zm,nregarding all coordinate points and calculating the difference thereof,and setting the value as H0.0, 0.0 when no operation is performed to themeasured value; subsequently regarding the maximum fluctuation width andpitch predetermined in the Z axis direction, inclining the virtual planeABCD against the surface plate by fixing end A of the virtual plane ABCDand respectively raising and lowering either end C and end B atprescribed fluctuation widths B, C; calculating a distance (height)(Zm,n) B, C from all coordinate points (Xm, Yn) on the virtual planeABCD to the corresponding coordinate point of the upper surface of theplate-like material each time the inclination is changed, and searchingfor the maximum value and the minimum value of (Zm,n) B, C andcalculating the different H (B,C) thereof; and repeating the search forall combination of B and C set in advance, and deciding the smallestvalue of H(B,C) calculated with all combinations of B and C as aparallel plane of a plane in which the virtual plane ABCD will be of aminimum machining cost.
 2. The method of determining a machined surfaceof a plate-like material according to claim 1, wherein, upon reversingand mounting the plate-like material on the surface plate of themachining machine, a measurement point in which a height Z from thevirtual plane ABCD to the plate-like material is a smallest value in thevirtual plane ABCD with the minimum machining cost determined issearched, and the measurement point is set as a point that comes incontact with the surface plate. 3-10. (canceled)
 11. An apparatus fordetermining a machined surface of a plate-like material capable ofminimizing machining costs upon machining the plate-like material withtwo- or three-dimensional deformation to realize a uniform thickness,comprising: a system for setting a surface plate surface of a measuringdevice as coordinates (X,Y), setting orthogonal coordinates (X,Y,Z)formed from a Z coordinate that is perpendicular to the coordinates(X,Y) on the surface plate, mounting the plate-like material as anobject to be measured on the surface plate, and virtually configuringwith a computer a plane ABCD that is parallel to the XY plane in which adistance from the surface plate is H; a system for measuring a distance(height) Zm,n from coordinates (Xm, Yn) of the virtual plane ABCD tocoordinates (Xm, Yn) of an upper surface of the plate-like material asan object to be measured m times in the X direction and n times in the Ydirection while changing the coordinates (X, Y) for all areas of theplate-like material, and storing the measured data in a storageapparatus of the computer; a system for searching for a maximum valueand a minimum value of Zm,n regarding all coordinate points andcalculating the difference thereof, and setting the value as differenceH 0.0, 0.0 when no operation is performed to the measured value;subsequently regarding the maximum fluctuation width and pitchpredetermined in the Z axis direction, a system for inclining thevirtual plane ABCD against the surface plate with a computer by fixingend A of the virtual plane ABCD and respectively raising and loweringend C and end B at prescribed fluctuation widths B, C; a system forcalculating a distance (height) (Zm,n) B, C from all coordinate points(Xm,Yn) on the virtual plane ABCD to the corresponding coordinate pointof the upper surface of the plate-like material each time theinclination is changed, searching for the maximum value and the minimumvalue of (Zm,n) B, C and calculating the difference H (B,C) thereof, andrepeating the search for all combinations of B and C in advance; whereinthe smallest value of H(B,C) is determined to be a parallel plane of aplane in which the virtual plane ABCD will be of a minimum machiningcost.
 12. The apparatus for determining a machined surface of aplate-like material according to claim 11, wherein, upon reversing andmounting the plate-like material on the surface plate of the machiningmachine, a measurement point in which a height Z from the virtual planeABCD to the plate-like material is a smallest value in the virtual planeABCD with the minimum machining cost is searched, and the measurementpoint is set as a point that comes in contact with the surface plate.13-20. (canceled)
 21. The method of determining a machined surface of aplate-like material according to claim 1, wherein, upon reversing andmounting the plate-like material on the surface plate of the machiningmachine, the smallest value Zmin of the height Z from the virtual planeABCD to the plate-like material is subtracted from a height of themeasurement point of four corners of the plate-like material in advance,and the obtained value is made to be a thickness of a spacer to beinserted in the four corners upon setting the plate-like material on themachining machine.
 22. The method of determining a machined surface of aplate-like material according to claim 21, wherein, when there isvariation in the plate-like material thickness, the thickness of thespacer is corrected for the amount of the variation.
 23. The method ofdetermining a machined surface of a plate-like material according toclaim 1, wherein the height of both the X direction and the Y directionof the coordinate axis of the plate-like material is measured at aposition of a pitch which is 20 mm or less.
 24. The method ofdetermining a machined surface of a plate-like material according toclaim 1, wherein the distance Z with the plate-like material is measuredwith a laser distance sensor or a contact distance sensor.
 25. Themethod of determining a machined surface of a plate-like materialaccording to claim 1, wherein, based on said data, inclination of abiaxial rotary-type machining table of an NC-controllable machiningmachine is adjusted in substitute for manually inserting a spacer at thefour corners of the plate-like material.
 26. A machining method ofdeciding a machined surface of a plate-like material with the methodaccording to claim 1, and, based on the decided machined surface,performing machining such as cutting work, grinding, and electricaldischarging to a plate-like material with two- or three-dimensionaldeformation to realize a uniform thickness.
 27. A machining method ofdeciding a machined surface of a plate-like material with the methodaccording to claim 1, and, based on the decided machined surface,surface grinding one surface of the plate-like material, and thereafterreversing and mounting the plate-like material on the surface plate toprocess the rear surface.
 28. A machining method of immovably fixing aplate-like material on the machining machine via adhesion orelectromagnetic adsorption, deciding optimal inclination conditionsthrough measurement with the method according to claim 1, thereafterusing a biaxial inclination mechanism of the surface plate of themachining machine, without reversing the material, to incline thesurface plate in parallel to a plane obtained with the optimalinclination conditions, and machining the material in this state. 29.Apparatus according to claim 11, wherein, upon reversing and mountingthe plate-like material on the surface plate of the machining machine,the smallest value Zmin of the height Z from the virtual plane ABCD tothe plate-like material is subtracted from a height of the measurementpoint of four corners of the plate-like material in advance, and theobtained value is made to be a thickness of a spacer to be inserted inthe four corners upon setting the plate-like material on the machiningmachine.
 30. Apparatus according to claim 29, wherein, when there isvariation in the plate-like material thickness, the thickness of thespacer is corrected for the amount of the variation.
 31. Apparatusaccording to claim 11, further comprising machining equipment forperforming machining such as cutting work, grinding, and electricaldischarging to a plate-like material with two- or three-dimensionaldeformation to realize a uniform thickness.
 32. Apparatus according toclaim 11, further comprising an apparatus for surface grinding onesurface of the plate-like material, and thereafter reversing andmounting the plate-like material on the surface plate to process therear surface.
 33. Apparatus according to claim 11, further comprising anapparatus for measuring the height of both the X direction and the Ydirection of the coordinate axis of the plate-like material at aposition of a pitch which is 20 mm or less.
 34. Apparatus according toclaim 11, further comprising an apparatus for measuring the distance Zwith the plate-like material with a laser distance sensor or a contactdistance sensor.
 35. Apparatus according to claim 11, further comprisingan apparatus for adjusting, based on said data, the inclination of abiaxial rotary-type machining table of an NC-controllable machiningmachine in substitute for manually inserting a spacer at the fourcorners of the plate-like material.
 36. A flattening device such as asurface grinding machine, a milling machine, or an electrical dischargemachine comprising the apparatus according to claim 11.